High density networking shelf and system

ABSTRACT

A system, a shelf, and a high density platform optimize the physical arrangement of cards to maximize cooling effectiveness and line card pitch while minimizing backplane trace lengths between line interface and switch fabric cards. The shelf and system and associated card arrangement supports scaling to a larger, double-size system that maintains the required length of backplane traces for card communications without compromising card cooling. Advantageously, the shelf and system maintains full NEBS compliance through an arrangement supporting full air intake/outtake through a front and/or back of the shelf or system, i.e. no side ventilation, and includes a false front to ensure all cards (switch fabric and line interface cards) are substantially flush with one another.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present patent/application is a continuation of U.S. patentapplication Ser. No. 14/085,343, filed Nov. 20, 2013, and entitled “HIGHDENSITY NETWORKING SHELF AND SYSTEM,” the contents of which areincorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to networking equipment. Moreparticularly, the present disclosure relates to a high density (HD)networking shelf and system that may be used in telecommunicationnetworks, data communications networks, and the like.

BACKGROUND OF THE DISCLOSURE

Networks are continuing to grow, with current and projected rates inexcess of 30% annualized increase in bandwidth. Such growth rates implynetwork bandwidth is doubling approximately every two-and-a-half years.At the same time, network hardware cost, space, and power consumptionallocations are staying roughly flat. Equipment manufacturers must,therefore, deliver substantial continuous reductions in per-bit metricsrelated to cost, space, and power. Telecommunication, datacommunication, high-performance computing, and the like systems aretypically deployed in physical hardware shelves that are mounted inracks or frames. For example, typical racks or frames are either 19,˜21, or 23 inches in practice. A rack unit (abbreviated as U or RU) is aunit of measure describing the height of equipment intended for mountingin a rack or frame, e.g. one RU equals 1.75 inches (44.45 mm) in height.Various standards associated with racks or frames are described byTelecordia's GR-63-CORE, “NEBS Requirements: Physical Protection” (April2012), European Telecoms Standards Institute (ETSI), American NationalStandard Institute (ANSI), etc.

A conventional system includes a number of vertically arranged cardsthat are inserted into a backplane in a physical shelf mounted on a rack(e.g., 19″, ETSI, or 21″ rack). A conventional system may also include acombination of vertically arranged cards and horizontally arranged cardsinserted into a backplane and/or midplane. Note, cards can also beinterchangeably referred to as modules, blades, circuit packs, etc.Generally, in networking systems, cards can be further divided intofunctionality with cards either being line cards and/or switch cards.The line cards provide input/output (I/O) to the shelf and typicallyinclude a plurality of physical media devices such as opticaltransceivers, etc. on a front of the cards. The line cards can bereferred to as I/O cards, interface cards, ingress/egress devices, andthe like. The switch cards (which can also be referred to as fabrics orswitch fabric cards) provide electrical and/or optical switchingfunctionality and/or other processing functionality and typically do notinclude physical I/O ports on a front of the cards.

What is needed is a shelf and system that preserves compliance tovarious specifications (e.g., NEBS), conforms to service provideroperational requirements, supports the high density card deployment, andthe like.

BRIEF SUMMARY OF THE DISCLOSURE

In an exemplary embodiment, a system includes a first set of cardsinsertable into the system, wherein a first air path for air flow coolsthe first set a second set of cards insertable into the system, whereina second air path for air flow cools the second set, wherein each of thesecond set have a different depth than the first set when inserted intothe system, wherein a recess portion is defined between the first setand the second set; at least one first fan for the first set, located inthe first air path that extends from the recess portion to exhaustopenings on a rear portion of the system; and at least one second fanfor the second set located in the second air path that extends from therecess portion to exhaust openings on a lower rear portion of thesystem. Each of the first air path and the second air path can be atleast partly physically separate from one another. The first air pathand the second air path each can begin at a lower front portion of thesystem and end at a rear portion of the system. The first set can behorizontally insertable into the system and the second set can bevertically insertable into the system. The system can be mountable in aframe. The first set each can include interface cards and the second seteach can include switch cards. An extension on the second set caninclude faceplates substantially flush with faceplates associated withthe first set. The system has no side ventilation. The system canfurther include a third set of cards insertable into the system, whereinthe third set is located adjacent to the second set, and wherein a thirdair path for air flow cools the third set.

In another exemplary embodiment, a shelf includes a first cageconfigured to receive a first set of cards, wherein a first air path forair flow cools the first set; a second cage configured to receive asecond set of cards, wherein a second air path for air flow cools thesecond set, wherein the second set have a different depth than the firstset when inserted into the shelf, wherein a recess portion is definedbetween the first set and the second set; at least one first fan for thefirst cage located in the first air path that extends from the recessportion to exhaust openings on a rear portion of the shelf; and at leastone second fan for the second cage located in the second air path thatextends from the recess portion to exhaust openings on a lower rearportion of the shelf. Each of the first air path and the second air pathcan be at least partly physically separate from one another. The firstair path and the second air path each can begin at a lower front portionof the shelf and end at a rear portion of the shelf. The first set canbe horizontally insertable into the first cage and the second set can bevertically insertable into the second cage. The shelf is mountable in aframe. The first set each can include interface cards and the second seteach can include switch cards. An extension on the second set caninclude faceplates substantially flush with faceplates associated withthe first set. The shelf has no side ventilation. The shelf can furtherinclude a third cage set configured to receive a third set of cards,wherein the third cage is located adjacent to the second cage, andwherein a third air path for air flow cools the third cage.

In a further exemplary embodiment, a rack includes one or more shelveseach including a first cage configured to receive a first set of cards,wherein a first air path for air flow cools the first set; a second cageconfigured to receive a second set of cards, wherein a second air pathfor air flow cools the second set, wherein the second set have adifferent depth than the first set when inserted into each shelf,wherein a recess portion is defined between the first set and the secondset; at least one first fan for the first cage located in the first airpath that extends from the recess portion to exhaust openings on a rearportion of the shelf; and at least one second fan for the second cagelocated in the second air path that extends from the recess portion toexhaust openings on a lower rear portion of the shelf. The one or moreshelves have no side ventilation.

In an exemplary embodiment, a system includes a first set of cardsinsertable into the system, wherein a first air path for air flow coolsthe first set; a second set of cards insertable into the system, whereina second air path for air flow cools the second set, wherein the secondset have a different depth than the first set when inserted into thesystem; an extension on the second set defining a recess portion betweenthe first set and the second set, wherein the first air path extendsfrom the recess portion to exhaust openings on a rear portion of thesystem; first fans for the first set, wherein the first air path extendsfrom the recess portion to exhaust openings on a rear portion of thesystem; and second fans for the second set, wherein the second air pathextends from the recess portion to exhaust openings on a lower rearportion of the system. Each of the first air path and the second airpath is physically separate from one another. Each of the first air pathand the second air path each begins at a lower front portion of thesystem and end at a rear portion of the system. The first set can behorizontally insertable into the system and the second set arevertically insertable into the system. The system can be mountable in aframe. The first set each can include interface cards and the second seteach can include switch cards. The extension can include faceplatessubstantially flush with faceplates associated with the first set. Thesystem has no side ventilation. The can further include a third set ofcards insertable into the system, wherein the third set is locatedadjacent to the second set, and wherein a third air path for air flowcools the third set.

In another exemplary embodiment, a shelf includes a first cageconfigured to receive a first set of cards, wherein a first air path forair flow cools the first set; a second cage configured to receive asecond set of cards, wherein a second air path for air flow cools thesecond set, wherein the second set have a different depth than the firstset when inserted into the shelf; an extension on the second setdefining a recess portion between the first set and the second set,wherein the first air path extends from the recess portion to exhaustopenings on a rear portion of the shelf first fans for the first cage,wherein the first air path extends from the recess portion to exhaustopenings on a rear portion of the shelf and second fans for the secondcage, wherein the second air path extends from the recess portion toexhaust openings on a lower rear portion of the shelf. Each of the firstair path and the second air path are physically separate from oneanother. The first air path and the second air path each can begin at alower front portion of the shelf and end at a rear portion of the shelf.The first set can be horizontally insertable into the first cage and thesecond set can be vertically insertable into the second cage. The shelfis mountable in a frame. The first set each can include interface cardsand the second set each can include switch cards. The extension caninclude faceplates substantially flush with faceplates associated withthe first set. The shelf has no side ventilation. The can furtherinclude a third cage set configured to receive a third set of cards,wherein the third cage is located adjacent to the second cage, andwherein a third air path for air flow cools the third cage.

In a further exemplary embodiment, a rack includes one or more shelveseach including a first cage configured to receive a first set of cards,wherein a first air path for air flow cools the first set; a second cageconfigured to receive a second set of cards, wherein a second air pathfor air flow cools the second set, wherein the second set have adifferent depth than the first set when inserted into the shelf; anextension on the second set defining a recess portion between the firstset and the second set, wherein the first air path extends from therecess portion to exhaust openings on a rear portion of the shelf; firstfans for the first cage, wherein the first air path extends from therecess portion to exhaust openings on a rear portion of the shelf; andsecond fans for the second cage, wherein the second air path extendsfrom the recess portion to exhaust openings on a lower rear portion ofthe shelf. The one or more shelves have no side ventilation.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated and described herein withreference to the various drawings, in which like reference numbers areused to denote like system components/method steps, as appropriate, andin which:

FIG. 1 is a perspective diagram of a high density platform;

FIG. 2 is a perspective diagram of a platform with a recessed portioncompared to a platform without the recessed portion to illustrate airflow;

FIG. 3 is a front perspective diagram of a high density platform;

FIG. 4 is a front view of the high density platform of FIG. 3;

FIG. 5 is a rear perspective diagram of the high density platform ofFIGS. 3-4;

FIG. 6 is a cross-sectional internal diagram of the high densityplatform of FIGS. 3-5;

FIG. 7 is a perspective view of an exemplary interface card for the highdensity platform of FIGS. 3-6;

FIG. 8 is a perspective view of an exemplary switch fabric card for thehigh density platform of FIGS. 3-6;

FIG. 9 is a perspective diagram of left side fabric fans and a ramp forthe high density platform of FIGS. 3-6; and

FIG. 10 is a front perspective diagram of a larger high density platformrelative to the high density platform.

DETAILED DESCRIPTION OF THE DISCLOSURE

In various exemplary embodiments, a high density (HD) networking shelfand system that may be used in telecommunication networks, datacommunication networks, and the like is described that optimizesphysical arrangement of cards to maximize cooling effectiveness and linecard pitch while minimizing backplane trace lengths between line andswitch cards. The shelf and system and associated card arrangementsupports scaling to a larger, double-size system that maintains therequired length of backplane traces for card communications withoutcompromising card cooling. Advantageously, the shelf and systemmaintains full NEBS compliance through an arrangement supporting fullair intake/outtake through a front and/or back of the shelf or system,i.e. no side ventilation, and includes a false front to ensure all cards(switch fabric and line interface cards) are substantially flush withone another.

Referring to FIG. 1, in an exemplary embodiment, a perspective diagramillustrates a high density platform 10. The high density platform 10 isdescribed in detail in commonly-assigned U.S. Pat. No. 8,154,867, filedApr. 2, 2010, issued Apr. 10, 2012, and entitled “HIGH DENSITY SWITCHINGPLATFORM WITH INTERBAY CONNECTIONS ARRANGEMENT,” the contents of whichare incorporated herein. The high density platform 10 includes a housing12 which can refer to any electronics rack, cabinet, case, frame, orother apparatus used to arrange and/or support a plurality of electroniccomponents such as cards, including interface cards 14, 16 and switchfabric cards 18. The housing 12 may be metal, plastic, or combination,or other suitable material and similar in construction to otherhousings, cabinets and/or racks used to hold electronic components inplace.

The housing 12 has a front side 22, a rear side 34 opposite the frontside 22, and a third side 30 adjacent to both the front side 22 and therear side 34. The housing 12 supports a first set of interface cards 14,a second set of interface cards 16, and a central set of switch fabriccards 18. The first set of interface cards 14 are arranged in a firstdirection 20. The second set of interface cards 16 are also arranged inthe first direction 20. The central set of switch fabric cards 18 isarranged orthogonally, i.e., perpendicular, to the first direction 20.Each of the first set of interface cards 14, the second set of interfacecards 16 and the central set of switch fabric cards 18 may optionally besurrounded by a separate metallic Faraday Cage including, for example, ametal mesh screen. The orthogonal arrangement of the switch fabric cards18 as compared with the interface cards 16, when combined with aplatform 10, allows faceplate interconnections from the first system tothe next without preventing removability of the switch fabric cards orinterface cards, due to cable dressing interference.

Each of the first set of interface cards 14, the second set of interfacecards 16 and the central set of switch fabric cards 18 may alsooptionally be held in place by a frame or other support structure thatmay hold the sets of circuit cards 14, 16 and 18 firmly in place andfacilitate removal and replacement of the circuit cards 14, such as forexample a card cage or similar structure. The first set of interfacecards 14, the second set of interface cards 16 and the central set ofswitch fabric cards 18 may all be removably inserted into the housing 12through the front side 22 of the housing 12, thereby allowing circuitcards 14, 16 and 18 to be inserted and removed.

The housing 12 includes a first ventilation chamber 24 adjacent to thefirst set of interface cards 14, a second ventilation chamber 26adjacent to the second set of interface cards 16 and a centralventilation chamber 28 adjacent to the central set of switch fabriccards 18. Each of the first ventilation chamber 24, the secondventilation chamber 26 and the central ventilation chamber 28 may besubstantially sealed except at the airflow entry and exit points inorder to facilitate directional airflow in each of the chambers. Thethird side 30 of the housing 12 has a side air access 32 locatedopposite to the central ventilation chamber 28 that is aligned with thecentral set of switch fabric cards 18. In this embodiment, the side airaccess 32 has openings therethrough forming a honeycomb pattern on thethird side 30. Optionally, the side air access 32 may have a single,large opening, a series of elongate slits or other openings tofacilitate the passing of ambient air through the side air access 32.The side air access 32 facilitates the flow of ambient air across thefirst set of interface cards 14, the second set of interface cards 16and the central set of switch fabric cards 18.

Referring to FIG. 2, in an exemplary embodiment, a perspective diagramillustrates the platform 10 with a recessed portion 40 compared to aplatform 50 without the recessed portion 40. The recessed portion 40 isformed due to the switch fabric cards 18 being shorter in depth than theinterface cards 14 and positioned orthogonally therefrom. FIG. 2illustrates the advantages of this card arrangement, i.e. horizontalfabric cards. The recessed portion 40 allows superior air flow intointerface cards 14 while space is shared with the fabric card section,and air easily goes through the front of the interface cards 14 to coolfaceplate optics thereon. The platform 50 can include vertically alignedcards for the interface cards 14 and the switch fabric cards 18. Here,enough air inlet must be left below a fiber manager to allow sufficientair flow. This space is not shared, just open air, and air must turnback towards faceplates as it rushes inward toward the rear of theshelf. One disadvantage though of the recessed portion 40 is that theswitch fabric cards 18 are recessed in the platform 10 relative to theinterface cards 14. This can have operational disadvantages withfaceplate indicators (e.g., LED lights) being offset or out of view aswell as difficulties in inserting/removing the switch fabric cards 18.

Referring to FIGS. 3-6, in an exemplary embodiment, various perspectivediagrams illustrate a high density platform 100. The high densityplatform 100 can be a shelf, a system, etc. forming a network element, anode, etc. in a network. FIG. 3 is a front perspective diagram of thehigh density platform 100, FIG. 4 is a front view of the high densityplatform 100, FIG. 5 is a rear perspective diagram of the high densityplatform 100, and FIG. 6 is a cross-sectional internal diagram of thehigh density platform 100. Relative to the high density platform 10, thehigh density platform 100 includes front and rear air intake/exhaustwithout side ventilation thereby maintaining NEBS compliance andincludes a modification of recessed portion 40 to provide an extensionsuch that switch fabric cards are substantially flush with interfacecards on a front side of the platform 100. Additionally, relative to thehigh density platform 10, the high density platform 100 is a half-racksystem that is scalable to a double (full rack) sized system whereas thehigh density platform 10 is a full rack sized system.

In an exemplary embodiment, the high density platform 100 can be anetwork element that may consolidate the functionality of amulti-service provisioning platform (MSPP), digital cross connect (DCS),Ethernet and/or Optical Transport Network (OTN) switch, dense wavedivision multiplexing (DWDM) platform, etc. into a single, high-capacityintelligent switching system providing Layer 0, 1, and 2 consolidation.In another exemplary embodiment, the high density platform 100 can beany of an OTN add/drop multiplexer (ADM), a SONET/SDH/OTN ADM, amulti-service provisioning platform (MSPP), a digital cross-connect(DCS), an optical cross-connect, an optical switch, a router, a switch,a wavelength division multiplexing (WDM) terminal, an access/aggregationdevice, etc. That is, the high density platform 100 can be any digitaland/or optical system with ingress and egress signals and switchingtherebetween of channels, timeslots, tributary units, packets, etc.utilizing OTN, SONET, SDH, Ethernet, IP, etc. In yet another exemplaryembodiment, the high density platform 100 can be a high-rate Ethernetswitch. While the high density platform 100 is generally shown as anoptical network element, the shelf and system are contemplated for usewith any switching fabric, network element, or network based thereon.

The high density platform 100 includes a housing 102 which can refer toany shelf, rack, cabinet, case, frame, or other apparatus used toarrange and/or support a plurality of electronic/optical components suchas cards, including interface cards 114 and switch fabric cards 116. Thehousing 102 may be metal, plastic, or combination, or other suitablematerial and similar in construction to other housings, cabinets and/orracks used to hold electronic/optical components in place. Further, thehousing 102 may be rack mounted in an ETSI, ANSI, etc. compliant rack orframe. The housing 102 has a front side 104, a rear side 106 oppositethe front side 104, a right side 108 adjacent to both the front side 104and the rear side 106, and a left side 110 opposite the right side andadjacent to both the front side 104 and the rear side 106. Air flow inthe high density platform 100 is between the front side 104 and the rearside 106; there is no air flow through or between the sides 108, 110.

The housing 12 supports a set of interface cards 114 and a set of switchfabric cards 116. The interface cards 114 are arranged in a firstdirection 120. The switch fabric cards 116 are arranged substantiallyorthogonally, i.e., perpendicular, to the first direction 120. In thisexemplary embodiment, the interface cards 114 are vertically aligned andthe switch fabric cards 116 are horizontally aligned. The cards 114, 116may optionally be surrounded by a separate metallic Faraday Cageincluding, for example, a metal mesh screen. The orthogonal arrangementof the switch fabric cards 116 as compared with the interface cards 114can form the recessed portion 40 as described herein. The high densityplatform 100 can include the recessed portion 40 for airflow whilehaving the switch fabric cards 116 substantially flush with theinterface cards 114 through an extension portion on the switch fabriccards 116. The extension portion provides a false front that extends thefaceplate of the switch fabric cards 116 to be flush with the interfacecards 114 while still maintaining open space forming the recessedportion 40.

The interface cards 114 can include optical transceivers, such as, forexample, 1 Gb/s (GbE PHY), 2.5 Gb/s (OC-48/STM-1, OTU1, ODU1), 10 Gb/s(OC-192/STM-64, OTU2, ODU2, 10 GbE PHY), 40 Gb/s (OC-768/STM-256, OTU3,ODU3, 40 GbE PHY), 100 Gb/s (OTU4, ODU4, 100 GbE PHY), etc. Again, theinterface cards 114 can be referred to as line cards, line blades, I/Omodules, etc. and can include a plurality of optical modules in thefront. For example, the optical modules can be pluggable modules suchas, without limitation, XFP, SFP, XENPAK, X2, CFP, CFP2, CFP4, etc.Further, the interface cards 114 can include a plurality of opticalconnections per module and each module may include a flexible ratesupport for any type of connection, such as, for example, 155 Mb/s, 622Mb/s, 1 Gb/s, 2.5 Gb/s, 10 Gb/s, 40 Gb/s, and 100 Gb/s, and any rate inbetween. The interface cards 114 can include wavelength divisionmultiplexing interfaces, short reach interfaces, and the like, and canconnect to other interface cards 114 on remote network elements, endclients, edge routers, and the like.

From a logical perspective, the interface cards 114 provide ingress andegress ports to the high density platform 100, and each interface card114 can include one or more physical ports. The switch fabric cards 116are configured to switch channels, timeslots, tributary units, packets,cells, etc. between the interface cards 114. For example, the interfacecards 114 can provide wavelength granularity (Layer 0 switching),SONET/SDH granularity such as Synchronous Transport Signal-1 (STS-1) andvariants/concatenations thereof (STS-n/STS-nc), Synchronous TransportModule level 1 (STM-1) and variants/concatenations thereof, VirtualContainer 3 (VC3), etc.; OTN granularity such as Optical Channel DataUnit-1 (ODU1), Optical Channel Data Unit-2 (ODU2), Optical Channel DataUnit-3 (ODU3), Optical Channel Data Unit-4 (ODU4), Optical Channel DataUnit-flex (ODUflex), Optical channel Payload Virtual Containers (OPVCs),ODTUGs, etc.; Ethernet packet granularity; Digital Signal n (DSn)granularity such as DS0, DS1, DS3, etc.; and the like. Specifically, theswitch fabric cards 116 can include both Time Division Multiplexed (TDM)(i.e., circuit switching) and packet switching engines. The interfacecards 114 and/or the switch fabric cards 116 can include redundancy aswell, such as 1:1, 1:N, etc. In an exemplary embodiment, the switchfabric cards 116 provide OTN, SONET, or SDH switching.

In an exemplary embodiment, the high density platform 100 can be 15-16RU with 12 slots for the interface cards 114 and 4 slots for the switchfabric cards 116. Here, the high density platform 100 can dissipatebetween 600-750 W. Further, the switch fabric cards 116 can be singlefabric or double fabric (with additional pins to the backplane from thesingle fabric). Additionally, the high density platform 100 contemplatesoperation in an ETSI, ANSI, 19″, or 23″ rack or frame.

Those of ordinary skill in the art will recognize the high densityplatform 100 can include other components which are omitted forillustration purposes, and that the systems and methods described hereinare contemplated for use with a plurality of different network elementswith the high density platform 100 presented as an exemplary type ofnetwork element. For the high density platform 100, other architecturesproviding ingress, egress, and switching therebetween are alsocontemplated for the systems and methods described herein. In general,the systems and methods described herein contemplate use with anynetwork element providing switching of OTN, SONET, SDH, etc. channels,timeslots, tributary units, wavelengths, packets, cells, etc.Furthermore, the high density platform 100 is merely presented as oneexemplary implementation for the systems and methods described herein.Those of ordinary skill in the art will recognize the systems andmethods can be used for practically any type of network element whichinclude separation of cards between horizontal alignment and verticalalignment.

In an exemplary embodiment, the high density platform 100 includescommon equipment 130, power connections 132, and a fiber manager 134.The common equipment 130 is utilized for operations, administration,maintenance, and provisioning (OAM&P) access; user interface ports; andthe like. The common equipment 130 can connect to a management systemthrough a data communications network (DCN). For example, the commonequipment 130 can include an Ethernet port for communication to the DCN.Additionally, the common equipment 130 can include a control planeprocessor configured to operate a control plane. The high densityplatform 100 can include an interface for communicatively coupling thecommon equipment 130, the interface cards 114, and the switch fabriccards 116 therebetween. For example, the interface can be a backplane,midplane, a bus, optical or electrical connectors, or the like. Theinterface cards 114 are configured to provide ingress and egress to theswitch fabric cards 116 and external to the high density platform 100.In an exemplary embodiment, the interface cards 114 can form ingress andegress switches with the switch fabric cards 116 as center stageswitches for a three-stage switch, e.g. a three-stage Clos switch. Otherconfigurations and/or architectures are also contemplated.

In an exemplary embodiment, the high density platform 100 includes therecessed portion 40 from FIG. 2 while maintaining keeping faceplates ofthe cards 114, 116 substantially flush. This is an important operationalconcern in having indicators on the cards 114, 116 simultaneouslyvisible as well as for ease of card insertion/removal for the switchfabric cards 116. This feature is enabled through an extension or falsefront on the switch fabric cards 116.

Referring to FIG. 7, in an exemplary embodiment, a perspective viewillustrates an exemplary interface card 114. The exemplary interfacecard 114 can include pluggable optical circuit packs 150 coupled toprocessing circuitry 152 coupled to a connector 154 for attachment to abackplane in the high density platform 100. The exemplary interface card114 can include latches 156 for secure attachment to the housing 102.The optical circuit packs 150 and the processing circuitry 152 can bemounted to a body 160, and the body 160 can be disposed to a faceplate162. The faceplate 162 can include the latches 156 and visual indicators(not shown) such as LEDs. The body 160 can be generally thinner than thefaceplate 162 and/or the connector 154 such that when the faceplate 162of a set of exemplary interface cards 114 are arranged side by side, asmall space, or slot, remains between the bodies of the exemplaryinterface cards 114, allowing air to pass between adjacent interfacecards 48. Other cards, including the switch fabric cards 116 similarlycan have a face that is thicker than the body in order to facilitatepassage of air between adjacent cards and to allow indicators, such aslight-emitting diodes, to be positioned within the faceplate 162.

Referring to FIG. 8, in an exemplary embodiment, a perspective viewillustrates an exemplary switch fabric card 116. The exemplary switchfabric card 116 can include connectors 170 interfacing to the backplaneof the housing 102 and coupled to printed circuit board (PCB) 172 whichcan include processing circuitry for the exemplary switch fabric card116. The exemplary switch fabric card 116 includes an extension 180disposed to the PCB 172. The extension 180 enables a faceplate 182 ofthe exemplary switch fabric card 116 to be substantially flush with thefaceplate 162 of the exemplary interface cards 114 while forming therecessed portion 40 between the exemplary interface cards 114 and theexemplary switch fabric card 116. The PCB 172 is shorter than the body160 of the exemplary interface card 114. However, with the extension180, the exemplary switch fabric card 116 extends out in the front side104 of the high density platform 100 about as much as the exemplaryinterface cards 114.

The extension 180 includes a back side 184 disposed to the PCB 172 andopposite the faceplate 182, a left side 186 adjacent to the faceplate182 and the back side 184, and a right side 188 opposite the left side186 and adjacent to the faceplate 182 and the back side 184. Thefaceplate 182 includes the include latches 156 for secure attachment tothe housing 102. That is, the faceplate 182, which is a false faceplate(because it extends from the PCB 172) includes the latches 156 forinsertion and removal of fabrics into the housing. The back side 184 caninclude an EMC wall at the front of the PCB 172 that also keeps the airin that moves across the exemplary switch fabric card 116 from right toleft. The sides 186, 188 can be perforated to allow air to enter andturn upwards into the vertical exemplary interface cards 114 cardsabove. Also, the faceplate 182 can be perforated to allow air to enterand turn upwards into the vertical exemplary interface cards 114 cardsabove. In an exemplary embodiment, the sides 186, 188 include slits, andthe faceplate 182 includes a plurality of holes. The faceplate 182 andthe sides 184, 186, 188 can be formed from a rigid material such thatthe extension 180 can be used to insert selectively or remove theexemplary switch fabric card 116 from the high density platform 100.

The faceplate 182 can include visual indicators of the status of theexemplary switch fabric card 116, such as LEDs for operational status,alarms, warnings, etc. In an exemplary embodiment, the exemplary switchfabric card 116 can include light pipes on the faceplate 182 to extendlight from LEDs at the back side 184 to the faceplate 182. In anotherexemplary embodiment, the faceplate 182 can include the LEDs thereonwith wiring extending from the PCB 172 to the faceplate 182 via eitherthe left side 186 or the right side 188. Variously, the faceplate 182can be referred to as a false front or false faceplate since it isactually a faceplate on the extension 180. Advantageously, the extension180 enables the recessed portion 40 to be formed for airflow efficiencyin the high density platform 100 while providing operational benefits ofhaving the faceplates 162, 182 substantially flush on the front side104.

Referring back to FIGS. 3-6, airflow is confined to the front side 104and the rear side 106 thereby maintaining NEBS compliance. There are novents or openings for airflow on the sides 108, 110. The high densityplatform 100 includes two separate airflow paths—a first air path forthe interface cards 114 and a second air path for the switch fabriccards 116. The first air path starts at a lower portion of the frontside 104 at three points 200, 202, 204. The first point 200 for thefirst air path is through the false faceplates 182 of the switch fabriccards 116 and through the recessed portion 40. The second point 202 isthrough a ramp 210 that is part of left side fabric fans 220.Specifically, the ramp 210 extends the depth of the recessed portion 40and opens at the front side 104 and allows air through to the interfacecards 114. Behind the ramp 210 and extending to the rear side 106 arethe left side fabric fans 220. The third point 204 is under the fibermanager 134.

The first air path includes interface fans 222 located above theinterface cards 114 (shown in FIG. 6). The interface fans 222 create thefirst air path from the points 200, 202, 204 to exhaust openings 224 onan upper portion of the rear side 106 (shown in FIG. 5). From the points200, 202, 204, the air is drawn upward by the interface fans 222 throughthe cage of the interface cards 114 to the exhaust openings 224. In thismanner, the air flow for the first air path is confined to the interfacecards 114, not the switch fabric cards 116. The second air path startsat a point 230 to the right of the switch fabric cards 116. The point230 includes perforations for air intake on the right side of the switchfabric cards 116. The left side fabric fans 220 (shown in FIG. 6) drawthe air from the point 230 back through the switch fabric cards 116 toan exhaust opening 232 on the lower rear left on the rear side (shown inFIG. 5). Again, the air flow for the second air path is confined to theswitch fabric cards 116 and not the interface cards 114. Advantageously,airflow for both the air paths is front to rear. Note, other embodimentsconsistent with the first air path and the second air path are alsocontemplated herein. For example, the second air path is from right toleft, but in another exemplary embodiment, this could be left to rightwith the fabric fans 220 located on the right side.

Referring to FIG. 9, in an exemplary embodiment, a perspective diagramillustrates the left side fabric fans 220 and the ramp 210. The fabricfans 220 draw air in from the right side where the switch fabric cards116 sit and exhaust out the left side where it turns to the rear of theshelf. The ramp 210 at the front serves the same purpose as the falsefaceplates 182 on the switch fabric cards 116, to allow air to enter thefront of the shelf and turns upwards in the second chimney for theinterface cards 114.

Referring to FIG. 10, in an exemplary embodiment, a front perspectivediagram illustrates a larger high density platform 300 relative to thehigh density platform 100. The larger high density platform 300 hastwice the physical capacity of the high density platform 100. The largerhigh density platform 300 is an integrated hardware system similar infeatures as the high density platform 100 described herein. For example,the high density platform 100 can take 15-16 RUs (e.g., about half arack or frame) whereas the larger high density platform 300 can take anentire rack or frame. The larger high density platform 300 iseffectively two of the high density platforms 100 in one frame with thebottom one being flipped horizontally such that all of the switch fabriccards 116 are together and there are two sets of interface cards 114—atop set and a bottom set. In this configuration, backplane traces areminimized between the switch fabric cards 116 and the interface cards114. The larger high density platform 300 can include the falsefaceplates 182 and the front-to-rear airflow as described herein for thehigh density platform 100.

Advantageously, the high density platform 100 includes horizontal andvertical cards coexisting in the same system that is a backplanedesigned system as opposed to a midplane designed system (i.e., it isnot unusual to find a midplane designed system with vertical cards onone side and horizontal on the other side). Additionally, the highdensity platform 100 effectively recesses the effective front of thehorizontal fabric cards with a false faceplate. This allows thehorizontal cards to be cooled from right to left in a separate airchimney from the interface cards while the front area of the fabriccards services as air inlet and plenum for the interface card bottom totop vertical airflow chimney.

In this new system design, the fabric card slots were removed from thecard cage that houses the interface card slots to allow each interfacecard to be wider pitch in order to increase interface card space andcooling capability of the interface cards. The switch fabric cards werethen moved to their own cage but arranged horizontally below theinterface card cage so that the backplane trace lengths would remainshort enough to allow high-speed 25 Gbps+ between all interface slotsand all fabric slots. Additionally, the switch fabric cards are maderecessed at the front with a false faceplate to allow more air intake tothe interface cards above, reducing the space required between theinterface and switch fabric card cages. The switch fabric cards are intheir own cooling chimney using side to side air flow that maintainsfront system air intake and rear system air exhaust.

This system allows more interface cards to fit in an ETSI wide shelf(rack) of sufficient card pitch to house newer optic modules such asCFP2 and CFP4 for adequate cooling. The interface card cooling isincreased while maintaining short backplane traces between interface andswitch fabric cards that are oriented horizontally below the interfacecards. Without this new system, a system would need to have at least oneof the following attributes: 1) 23″ wide rack instead of ETSI wide rackto fit all the cards, or 2) less interface cards, e.g. 10× interfacecards instead of 12× interface cards, or 3) interface card pitch=1.31″or less instead of interface card pitch=1.42″. This compromise in pitchis enough to reduce cooling and make some interface card types difficultto design and more expensive to manufacture.

In an exemplary embodiment, a system includes one or more cardsvertically insertable into a backplane; one or more cards horizontallyinsertable into the backplane, wherein the one or more cardshorizontally insertable include a false faceplate that is substantiallyflush with a faceplate of the one or more cards vertically insertablewhen each is inserted into the backplane; wherein a first air path isdefined for air flow to cool the one or more cards verticallyinsertable; wherein a second air path is defined for air flow to coolthe one or more cards horizontally insertable, wherein each of the firstair path and the second air path begin at a front portion of the systemand end at a rear portion of the system; a recess portion between theone or more cards vertically insertable and the one or more cardshorizontally insertable, wherein the recess portion is formed by anextension on each of the one or more cards horizontally insertable,wherein the first air path extends from the recess portion to exhaustopenings on a rear portion of the system, wherein interface fans arelocated above the one or more cards vertically insertable, wherein thefirst air path extends from lower portions of the front portion of thesystem to exhaust openings on a rear portion of the system; and fabricfans located on a side of the one or more cards horizontally insertable,wherein the second air path extends from an opening on an opposite sidefrom the fabric fans to exhaust openings on a lower rear portion of thesystem. The first air path and the second air path can be separate. Thefaceplate can include light pipes to display visual indicators from theone or more cards horizontally insertable. The one or more cardshorizontally insertable are shorter in depth than the one or more cardsvertically insertable and the false faceplate extends the one or morecards horizontally insertable to be substantially equal in depth to theone or more cards vertically insertable. The one or more cardsvertically insertable can include a first set of cards located above theone or more cards horizontally insertable, and the system furtherincludes one or more cards including a second set of cards verticallyinsertable located below the one or more cards horizontally insertable.The system can be mountable in a 19″, ETSI, or 21″ rack or frame.

In another exemplary embodiment, a shelf includes a housing; a firstcage in the housing for vertically insertable cards; a second cage inthe housing for horizontally insertable cards, wherein the second cageis shorter in depth than the first cage thereby forming a recess portiontherebetween, wherein the horizontally insertable cards each include afalse faceplate that is substantially flush with a faceplate of thevertically insertable cards when each is inserted into their associatedcage; wherein a first air path is defined for air flow to cool the firstcage; wherein a second air path is defined for air flow to cool thesecond cage, wherein each of the first air path and the second air pathbegin at a front portion of the housing and end at a rear portion of thehousing, wherein the first air path extends from the recess portion toexhaust openings on a rear portion of the housing; and interface fanslocated above the first cage, wherein the first air path extends fromlower portions of the front portion of the housing to exhaust openingson a rear portion of the housing, and fabric fans located on a side ofthe second cage, wherein the second air path extends from an opening onan opposite side from the fabric fans to exhaust openings on a lowerrear portion of the housing. The first air path and the second air pathcan be separate. The false faceplate can include light pipes to displayvisual indicators from the horizontally insertable cards. Thehorizontally insertable cards are shorter in depth than the verticallyinsertable cards, and the false faceplate extends the horizontallyinsertable cards to be substantially equal in depth to the verticallyinsertable cards. The first cage can include a first cage located abovethe second cage, and the shelf further includes another cage locatedbelow the second cage. The shelf can be mountable in a 19″, ETSI, or 21″rack or frame.

In a further exemplary embodiment, a high density platform includes ahousing mountable in a 19″ rack; one or more cards vertically insertableinto a backplane of the housing; one or more cards horizontallyinsertable into the backplane, wherein the one or more cardshorizontally insertable include a false faceplate that is substantiallyflush with a faceplate of the one or more cards vertically insertablewhen each is inserted into the backplane; wherein the one or more cardshorizontally insertable are shorter in depth than the one or more cardsvertically insertable and the false faceplate extends the one or morecards horizontally insertable to be substantially equal in depth to theone or more cards vertically insertable while concurrently forming anopen recess portion between the one or more cards horizontallyinsertable and the one or more cards vertically insertable for air flow;wherein interface fans are located above the one or more cardsvertically insertable, wherein a first air path extends from the openrecess portion to exhaust openings on a rear portion of the housing; andwherein fabric fans located on a side of the one or more cardshorizontally insertable, wherein a second air path extends from anopening on opposite side from the fabric fans to exhaust openings on alower rear portion of the housing.

Although the present disclosure has been illustrated and describedherein with reference to preferred embodiments and specific examplesthereof, it will be readily apparent to those of ordinary skill in theart that other embodiments and examples may perform similar functionsand/or achieve like results. All such equivalent embodiments andexamples are within the spirit and scope of the present disclosure, arecontemplated thereby, and are intended to be covered by the followingclaims.

What is claimed is:
 1. A system, comprising: a first set of cardsinsertable into the system, wherein a first air path for air flow coolsthe first set; a second set of cards insertable into the system, whereina second air path for air flow cools the second set, wherein each of thesecond set have a different depth than the first set when inserted intothe system, wherein a recess portion is defined between the first setand the second set; at least one first fan for the first set, located inthe first air path that extends from the recess portion to exhaustopenings on a rear portion of the system; and at least one second fanfor the second set located in the second air path that extends from therecess portion to exhaust openings on a lower rear portion of thesystem.
 2. The system of claim 1, wherein each of the first air path andthe second air path is at least partly physically separate from oneanother.
 3. The system of claim 1, wherein the first air path and thesecond air path each begins at a lower front portion of the system andend at a rear portion of the system.
 4. The system of claim 1, whereinthe first set are horizontally insertable into the system and the secondset are vertically insertable into the system.
 5. The system of claim 1,wherein the system is mountable in a frame.
 6. The system of claim 1,wherein the first set each comprises interface cards and the second seteach comprise switch cards.
 7. The system of claim 1, wherein anextension on the second set comprises faceplates substantially flushwith faceplates associated with the first set.
 8. The system of claim 1,wherein the system has no side ventilation.
 9. The system of claim 1,further comprising: a third set of cards insertable into the system,wherein the third set is located adjacent to the second set, and whereina third air path for air flow cools the third set.
 10. A shelf,comprising: a first cage configured to receive a first set of cards,wherein a first air path for air flow cools the first set; a second cageconfigured to receive a second set of cards, wherein a second air pathfor air flow cools the second set, wherein the second set have adifferent depth than the first set when inserted into the shelf, whereina recess portion is defined between the first set and the second set; atleast one first fan for the first cage located in the first air paththat extends from the recess portion to exhaust openings on a rearportion of the shelf; and at least one second fan for the second cagelocated in the second air path that extends from the recess portion toexhaust openings on a lower rear portion of the shelf.
 11. The shelf ofclaim 10, wherein each of the first air path and the second air path isat least partly physically separate from one another.
 12. The shelf ofclaim 10, wherein the first air path and the second air path each beginsat a lower front portion of the shelf and end at a rear portion of theshelf.
 13. The shelf of claim 10, wherein the first set are horizontallyinsertable into the first cage and the second set are verticallyinsertable into the second cage.
 14. The shelf of claim 10, wherein theshelf is mountable in a frame.
 15. The shelf of claim 10, wherein thefirst set each comprises interface cards and the second set eachcomprise switch cards.
 16. The shelf of claim 10, wherein an extensionon the second set comprises faceplates substantially flush withfaceplates associated with the first set.
 17. The shelf of claim 10,wherein the shelf has no side ventilation.
 18. The shelf of claim 10,further comprising: a third cage set configured to receive a third setof cards, wherein the third cage is located adjacent to the second cage,and wherein a third air path for air flow cools the third cage.
 19. Arack, comprising: one or more shelves each comprising: a first cageconfigured to receive a first set of cards, wherein a first air path forair flow cools the first set; a second cage configured to receive asecond set of cards, wherein a second air path for air flow cools thesecond set, wherein the second set have a different depth than the firstset when inserted into each shelf, wherein a recess portion is definedbetween the first set and the second set; at least one first fan for thefirst cage located in the first air path that extends from the recessportion to exhaust openings on a rear portion of the shelf; and at leastone second fan for the second cage located in the second air path thatextends from the recess portion to exhaust openings on a lower rearportion of the shelf.
 20. The rack of claim 19, wherein the one or moreshelves have no side ventilation.